Astronomers Detect Seismic Ripples In Oldest Known Spiral Galaxy

A recently captured image of a distant, ancient galaxy may contribute to scientists' comprehension of its formation and shed light on the origins of our Milky Way. BRI 1335-0417, aged over 12 billion years, stands as the oldest and most distant spiral galaxy identified in our universe.

Dr. Takafumi Tsukui, the primary author, highlighted that the advanced ALMA telescope enabled them to scrutinize this ancient galaxy with significantly enhanced detail, according to Phys.org. 

"Specifically, we were interested in how gas was moving into and throughout the galaxy," Dr. Tsukui said. "Gas is a key ingredient for forming stars and can give us important clues about how a galaxy is fueling its star formation."

In this instance, the researchers not only succeeded in recording the movement of the gas surrounding BRI 1335-0417 but also unveiled the formation of a seismic wave groundbreaking discovery for this early type of galaxy. The findings have been published in the Monthly Notices of the Royal Astronomical Society.

The disk of the galaxy, characterized by a flattened assembly of rotating stars, gas, and dust, exhibits a motion reminiscent of ripples spreading on a pond following the impact of a thrown stone.

"The vertically oscillating motion of the disk is due to an external source, either from new gas streaming into the galaxy or by coming into contact with other smaller galaxies," Dr. Tsukui said. "Both possibilities would bombard the galaxy with new fuel for star formation.

"Additionally, our study revealed a bar-like structure in the disk. Galactic bars can disrupt gas and transport it towards the galaxy's center. The bar discovered in BRI 1335-0417 is the most distant known structure of this kind. Together, these results show the dynamic growth of a young galaxy."

Due to the considerable distance of BRI 1335-0417, its light requires an extended duration to reach Earth. The images observed through a telescope today offer a glimpse into the galaxy's formative years, harking back to a time when the universe was merely 10% of its present age.

"Early galaxies have been found to form stars at a much faster rate than modern galaxies. This is true for BRI 1335-0417, which, despite having a similar mass to our Milky Way, forms stars at rate a few hundred times faster," co-author Associate Professor Emily Wisnioski said.

"We wanted to understand how gas is supplied to keep up with this rapid rate of star formation.

"Spiral structures are rare in the early universe, and exactly how they form also remains unknown. This study also gives us crucial information on the most likely scenarios.

"While it is impossible to observe the galaxy's evolution directly, as our observations only give us a snapshot, computer simulations can help piece the story together."